The fired Minneapolis police officer seen in a video with his knee on George Floyd's neck has been arrested and charged with third-degree murder and manslaughter, according to Hennepin County Attorney Mike Freeman.

"The investigation is ongoing," Freeman said, adding that he anticipated charges against the other three officers involved in the incident.

"We entrust our police officers to use certain amounts of force to do their job to protect us. They commit a criminal act if they use this force unreasonably," he said.

The death of Floyd has led to protests in cities across the nation and questions about the justice system when Americans of color are killed by police. There have been multiple protests with looting, fires and property damage in the Twin Cities, and the Minnesota governor, while acknowledging "visceral pain," has called for order.

Protests continued Friday for a fourth day in Minneapolis.

The evidence in the case includes a cell phone video of the incident, body worn cameras, witness statements, a preliminary report from medical examiner, and discussions with an expert, Freeman said.

The criminal complaint says, "(Former officer) Derek Michael Chauvin caused the death of George Floyd by perpetrating an act eminently dangerous to others and evincing a depraved mind without regard for human life."

If convicted of third-degree murder and second-degree manslaughter, Chauvin would face up to 25 years in prison on the first charge and up to 10 years on the second.

A preliminary autopsy report by the Hennepin County Medical Examiner found "no physical findings that support a diagnosis of traumatic asphyxia or strangulation," according to the criminal complaint released by the Hennepin County Attorney's Office.

The report added: "The combined effects of Mr. Floyd being restrained by the police, his underlying health conditions and any potential intoxicants in his system likely contributed to his death."

Chauvin had his knee on Floyd's neck for 8 minutes, 46 seconds in total, and 2 minutes, 53 seconds after Floyd was unresponsive, according to the criminal complaint.

Read the criminal complaint

Chauvin was taken into custody Friday by the Minnesota Bureau of Criminal Apprehension, according to Minnesota Department of Public Safety Commissioner John Harrington.

Chauvin and three other officers detained Floyd in handcuffs Monday after he allegedly used a counterfeit bill at a convenience store, police have said. Outrage grew in the form of protests after a video surfaced showing a Minneapolis police officer kneeling on Floyd's neck. The 46-year-old, who was unarmed, cried out that he couldn't breathe.

Governor pleads for order

Minnesota Gov. Tim Walz pleaded for order in his own news conference Friday as fires continued to burn in the Twin Cities, spewing what Walz said was "symbolic of decades and generations of pain, of anguish."

"What the world has witnessed since the killing of George Floyd on Monday has been a visceral pain, a community trying to understand who we are and where we go from here," the governor said at a news conference.

Acknowledging protesters' pain, Walz said disorder in the streets distracts officials and the community from addressing the issues at hand.

"As we put a presence on the street to restore order, it is to open that space, to seek justice and heal what happened," he said. "I will not in any way not acknowledge that there is going to be that pain, but my first and foremost responsibility to the state of Minnesota is the safety and security of all citizens. We cannot have the looting and recklessness that went on."

Among the buildings set ablaze overnight was the Minneapolis Police Department's Third Precinct, where protesters chanted Floyd's name and "I can't breathe." Some tossed fireworks toward the precinct, which is the one closest to where the incident was captured on video.

Officers form a line Friday along Lake Street near Hiawatha Avenue as fires burn following a night of unrest and protests over the death of George Floyd in Minneapolis.

State police, donning protective gear and carrying batons, lined up Friday morning near the site littered with debris and sprayed mace at protesters who got too close. Some responded by throwing projectiles at the officers as others fled.

"There are no words in the English language that will convey the despair that I felt watching that man's life leave his body and him scream out for his mother," Alicia Smith, a community organizer, said Thursday afternoon of watching the video this week. "I heard my son saying, 'Mama, save me.'"

"My kids are little boys, and my son asked me, 'Am I going to live to be a grown-up?'" she told CNN. "I've got to ruin his innocence and tell him how to exist as a young black boy in this country."

Meantime, a CNN crew has been released from police custody in Minneapolis after they were arrested Friday during a live broadcast at the site after clearly identifying themselves to officers. CNN correspondent Omar Jimenez was placed in handcuffs while the cameras rolled, shortly followed by producer Bill Kirkos and photojournalist Leonel Mendez.

The state patrol said the crew was "released once they were confirmed to be members of the media." CNN disputed that characterization, saying, "Our CNN crew identified themselves, on live television, immediately as journalists."

"We're doing OK, now," Jimenez said, reporting again from downtown. "There were a few uneasy moments there."

Outrage grows to other cities

The Minneapolis Police Department said it evacuated staff from the Third Precinct for safety reasons. Authorities had set up a fence around it, but protesters pushed it over, officials said.

City officials warned protesters Thursday night to leave the precinct area, saying it may be in danger of exploding due to "unconfirmed reports" of severed gas lines.

Minneapolis protests escalate following death of George Floyd

More than 500 Minnesota National Guard personnel mobilized to several locations in the Minneapolis area, including banks, grocery stories and pharmacies.

Another community organizer, Shanene Herbert, told CNN Thursday before the night's events that young people had "every right to be angry."

"They have experienced trauma," she said. "Seeing your friends, your families and even yourself harassed by the police and killed by the police, it's traumatic. And they don't know what to do with that."

The Minneapolis mayor criticized the violent incidents.

"What we've seen over the past several hours and the past couple of nights in terms of looting is unacceptable," Mayor Jacob Frey told reporters. "Our communities cannot and will not tolerate it."

But protesters in Minneapolis were not alone. In New York, Denver, Phoenix, Memphis and Columbus, Ohio, demonstrators demanded justice for Floyd, gathering in large crowds even as experts warned people to avoid big gatherings amid the coronavirus pandemic.

Right next door, in St. Paul, Minnesota, more than 170 businesses were damaged or looted, the city's police department said early Friday. St. Paul Mayor Melvin Carter said the anger was understandable, calling video of Floyd's death "nauseating."

He acknowledged concerns about the rioting and looting, but said there was a deeper, root problem that needed to be addressed.

"In order to get to the bottom of this, we have to understand where the rage is coming from in the first place," he said. "As we all know, we've seen video after video ... we've seen that the people responsible go free. And it seems no one gets held accountable."

Seven people were shot overnight Thursday in Louisville, Kentucky, during protests over a separate case, the death of EMT Breonna Taylor during a March police encounter. Meantime, the Ohio statehouse was broken into and damaged during protests Thursday evening in Columbus, the state Department of Public Security confirmed to CNN Friday.

Denver Mayor Michael Hancock pleaded with people to demonstrate peacefully, writing on Twitter, "March for justice and to see it served, but please march in peace."

About 70 people were arrested Thursday in New York, said New York Police Department Detective Adam Navarro, as crowds gathered near Union Square to protest Floyd's death. Charges range from obstruction of governmental administration to criminal possession of a weapon after a woman pulled a switchblade at Union Square, a law enforcement official said.

CNN's Sara Sidner reported from Minneapolis while Faith Karimi and Dakin Andone wrote from Atlanta. CNN's Steve Almasy, Kara Devlin, Hollie Silverman and Joe Sutton contributed to this report